The polymerization of butadiene during processing of hydrocarbons is a matter of concern, because it causes formation of unwanted polymers and results in loss of yield of end product and makes the process un-economical. Further, the butadiene also gets dimerized, which further enhances the wastage, and thereby, further enhances cost of production.
The prior art discloses use of quinone methide (QM) or its derivatives including 4-benzylidene-2,6-di-tert-butylcyclohexa-2,5-dienone, and use of nitroxide (i.e. nitroxyl) compounds including 1 oxyl-2,2,6,6-tetramethylpiperidin-4-ol or 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl (or 4 Hydroxy Tempo or 4HT) as polymerization inhibitor. The PCT publication no. WO 2002/33026 (PCT/US2001/30954) and US publication no. US 2009/0114878A1 disclose combination of quinone alkide/methide and nitroxyl compounds. However, the inventor has found [refer to examples] that main problem of using the QM or its derivatives, or nitroxides including 4HT is that these have to be used in higher amounts to achieve commercially acceptable level (acceptable by the industry) of inhibition, and such higher amount not only results in increase of cost of the process, but also results in formation of undesired products due to unstable nature of QM or its derivatives and nitroxides including 4HT.
Therefore, the industry is aiming for additive composition wherein the dosage of components of compositions of the prior art, particularly of the QM or its derivatives, and the nitroxides (i.e. nitroxyl) compounds including 4HT can be minimized or reduced. Any effort in the direction of lowering the consumption of these components will lessen the problem of industry, and the resulted composition will be economical as well as safe for human being.